A microcomputer system has been proposed to permit individuals to control and calculate their share of heating costs. In this proposed prior art system, which is described in "Dispositif de Comptage Individuel et d'Autoregulation de Chauffage Collectif," French Pat. No. 2,548,766 of Pierre Mumbach, published on Jan. 11, 1985, each apartment has its own microcomputer with a keyboard and display. Each microcomputer is connected to an ambient temperature sensor within the apartment, to probes located on the radiators in the apartment, and to a central computer housed in a common area that contains the building's heating installation. The central computer is also connected to an exterior temperature sensor and to a heating control circuit. This proposed system is said to permit display in each apartment of the temperature, of the daily price of heat consumption, and of the costs of heat consumption for the season, while permitting the user to regulate the heating in the apartment.
Retrofitting a metering system to accurately measure the actual cost of energy consumed in each unit of a commonly heated building, however, can be quite expensive, and may present significant difficulties.